This invention relates to a method of measuring tools and/or workpieces and is intended especially, but not exclusively for use at adaptive measuring with feed-back of the evaluated measuring result to the tool.
The conventional measuring methods of controlling tool wear are, besides direct optical inspection,
(a) detection of sound or light reflexes from tool-workpiece, which reflexes have been generated from an external source,
(b) mechanic contact measuring, and
(c) analysis of sound waves in workpiece or tool, which waves come from a transducer designed for this purpose.
Of these methods (a)-(c), which are feed-back methods for controlling the tool in response to wear, the methods (a) and (b) as they are developed to-day, are very sensitive to the severe environment prevailing at all cutting operations. The methods, furthermore, imply high requirements on accessibility. the costs in connection with these methods are high.
The method (c) is applied generally to crack detection, and also for determining greater distances. The use of ultrasound for measuring in metals, however, implies serious dissolution problems, due to the great sound speeds. The method (c), besides, is sensitive to interferences and has not been successfully applicable in connection with machining.
The present invention as it is defined in the attached claims renders it possible to eliminate the aforesaid disadvantages of the known measuring methods, and at the same time provides new possibilities for measuring accurately complicated tools and workpieces during the ongoing machining operation, as will become apparent from the description below.
Due to the special prerequisites applying to electroerosive machining, spark machining, the invention has a natural field of application also here.